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What is an angle?

Angles are all around us. An angle is created when two straight lines meet.

Look at the picture below. Two of the pairs of pencils show angles - can you work out which ones?

an arrangement of pencil

If your answer was the pair on the left and the pair on the right, then you are correct! The pair in the middle does not show an angle because the lines do not touch.

The picture below shows a right angle. This is a special type of angle that is a quarter of a full turn.

Right angle
pencils arranged in a right angle, measured with a set square

You can check whether an angle is a right angle by using a set square, like in the picture below.

pencils arranged in a right angle, measured with a set square
Half turn

So, three right angles make up three quarters of a full turn鈥

So, three right angles make up three quarters of a full turn鈥

Full turn

And four right angles make a full circle.

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Watch: Types of angles

An angle is a measure of a turn, measured in degrees or 掳. There are 360掳 in a full turn. You can find out the size of an angle using a protractor.

  • An angle less than 90掳 is acute.
  • An angle between 90掳 and 180掳 is obtuse.
  • An angle greater than 180掳 and less than 360掳 is reflex.
  • An angle of exactly 90掳 is a right-angle.
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Activities

Activity 1

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Activity 2

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Quiz

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NEW! Play Guardians: Defenders of Mathematica - the winter update
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More on Lines and angles

Find out more by working through a topic